10.3.1 Line Organization

The Prefetch module consists of two arrays, data and tag, each of which hold four lines. A data array consists of program instructions, program data or peripheral data. Address matches are based on the physical address, not the virtual address.

Each line in the tag array contains the following information:
  • Tag – Physical address of the data held in the data line
  • Valid bit

Each line in the data array, contains 16 bytes of data. Depending on the line, the data can be CPU instructions, CPU data or peripheral data.

The following figures illustrate the organization of a line.

Figure 10-2. Tag Line
Figure 10-3. Data Line